ILX: could not obtain service. invoked from within "ILX:

HI everyone,

I'm playing around with ILX and trying to send a SMS text message everytime a user logs into my device (on a particular URL) - for this I've used the Twilio example, but the .js file doesn't kick off at all: in the logs I have:

Rule /Common/plugin_twilio/irule_twilio <ACCESS_POLICY_AGENT_EVENT>: sendMessage failed for user: xxx@wontoso.com, ILX failure: ILX: could not obtain service. invoked from within "ILX::call $rpc_handle sendMessage $username $telephoneNumber $sender "

The call in my iRule:

set rpc_handle [ ILX::init plugin_twilio extension_twilio]

    if {[ catch { ILX::call $rpc_handle sendMessage $username $telephoneNumber $sender } result ] } {

.....

my index.js obviously has that method:

// Import the f5-nodejs module.

var f5 = require('f5-nodejs');

// Create a new rpc server for listening to TCL iRule calls.

var ILX = new f5.ILXServer();

const accountSid = 'somethingsecret'; // Your Account SID from www.twilio.com/console

const authToken = 'andmoresecret';  // Your Auth Token from www.twilio.com/console

const client = require('twilio')(accountSid, authToken);

ILX.addMethod('sendMessage', function(req, res) {

  console.log('Method Invoked, Arguments:', objArgs.params());

  var username = req.params()[0];

  var telephoneNumber = req.params()[1];

  var sender = req.params()[2];

  var message = username + ' logged in to F5';

  client.messages.create({

    body: message,

    to: telephoneNumber, // Text this number

    from: sender // From a valid Twilio number

  })

  .then(message => console.log(message.sid));

});

Any ideas?